Android4.2系でヘッダーが固定されない ref: http://qiita.com/satukun/items/be9bec622377d4bb59da
<script language="JavaScript" type="text/javascript" src="/js/jquery.mobile.custom.js"></script>
<div class="header" data-role="header" data-position="fixed">
~~~~~~
</div>
.header {
display: block;
position: fixed;
z-index: 100;
}